mathIf a student keeps asking similar questions the student needs to look at earlier replies and try to do the next one without help Jack. We can then check the answer but just telling the student how to do it time after time helps not in the least.
December 26, 2014

PhysicsThe 90 kg student was standing still, momentum of zero. there was a push for .0003 seconds then his speed was 5 m/s so change in momentum = 90*5 - 90*0 = 90*5
December 24, 2014

Physicsforce = change in momentum / change in time 90*5/.0003 in Newtons by the way .0003 is a very short pushing time, impractical I think. (typo?)
December 24, 2014

CULCULSexactly. I am a Naval Architect. We have a hydrostatic characteristic called "tons per inch" which is how many tons of cargo you can add to increase the draft by one inch as a function of draft. It is basically the water plane area * density of seawater :)
December 24, 2014

algerbracall the slope m then in general for any two points on a line of form y = m x + b the slope is change in y / change in x so for two points (x1 ,y1) and (x2 , y2) m = (y2-y1)/(x2-x1) the same is true for any other point on the line (x , y) so also m = (y2 - y) / (x2 - x) or m...
December 23, 2014

Big History Test (Check) Part1.The North's well-established government gave it a distinct advantage. <-- I suppose, but the main thing was the industrial base in the north and navy and railroads. I would have checked: The goal of the war changed from saving the Union to saving the Union and ...
December 23, 2014

PHYSICSHey - You are supposed to follow what I did, not just type any old number I give you!!!!! I did r = 3.19 You can multiply by 2 to get the diameter but you better decide to understand what I did first.
December 22, 2014

Earth scienceIsobars help me find fronts :) The cyclone is indeed counterclockwise in the Northern hemisphere (not south of the equator where the spin around a low is clockwise to conserve angular momentum). I agree with the rest
December 22, 2014

Math and PhyicsTension T in rope, on big mass M g - T = M a while the big mass is falling, the little mass goes up a distance h when the big mass hits ground, the little mass is moving with the speed that the big mass hits with, then coasts up until the kinetic energy of that speed is spent...
December 22, 2014

physicsNow this is very similar but easier than the one you threw up from the roof of the building. You try it. I have grand kids playing hockey now.
December 21, 2014

physicsThat t top in part B is the time to slow down on the way up from the top of the building to the max height. 10/9.81 seconds. THEN, it starts falling from that top point I called Htop. By the way it will pass the roof on the way down at 10 m/s down :)
December 21, 2014

HistoryHe sent General Zachary Taylor to claim an area of disputed land for the United States. http://en.wikipedia.org/wiki/South_Pass_%28Wyoming%29 The journey was surprisingly easy. the idea that it was God's plan for the nation to expand across the continent
December 21, 2014

BiologySometimes mechanical (rubbing) , sometimes chemical (reacting with O2), etc. The one thing you can count on is that whatever happens, it will end up losing heat to the environment :)
December 19, 2014

physicsstuff shoots out the rear, body moves forward Conservation of momentum (Newton #1) initial momentum before reaction = 0 so momentum of body/exhaust system remains zero forever therefore if exhaust moves back then body must move forward to keep the total momentum zero
December 19, 2014